Search Results (57)

Accurately characterizing the kinematics of slow-moving urban landslides remains a major scientific and operational challenge, because no single monitoring technique can simultaneously provide spatially continuous deformation patterns and reliable three-dimensional displacement measurements. This study investigates the spatial and temporal evolution of a slow-moving landslide affecting the University of Azuay campus in Cuenca (Ecuador), where ongoing ground deformation has caused structural damage to several buildings. An integrated monitoring strategy combining GNSS measurements, Sentinel-1 multi-temporal DInSAR analysis, and geophysical investigations (ERT and seismic profiling) was adopted to characterize landslide kinematics and constrain subsurface conditions. GNSS observations revealed that the north–south displacement component was dominant, with cumulative displacements exceeding 20 cm during the monitoring period (from July 2021 to June 2024), while east–west displacements were on the order of 10 cm. MT-DInSAR analysis delineated the spatial extent of the unstable area and identified mean deformation rates of up to approximately −1.5 cm/year in the central sector of the landslide. The combined interpretation of geodetic and geophysical data indicates that slope instability is controlled by saturated fine-grained layers and mechanical contrasts, with the basal sliding zone associated with weak levels of the Mangan Formation. Overall, the results demonstrate the value of a multi-sensor, component-wise monitoring strategy for improving the reliability of deformation estimates and for supporting landslide risk assessment and land-use planning in complex urban environments. Full article

Zinc–air batteries (ZABs) are crucial for renewable energy conversion and storage due to their cost-effectiveness, excellent safety, and superior cycling stability. However, developing efficient and affordable bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) at the air cathode remains a significant challenge. Manganese (Mn)-based materials, known for their tunable oxidation states, adaptable crystal structures, and environmental friendliness, are regarded as the most promising candidates. This review systematically summarizes recent advances in Mn-based bifunctional catalysts, concentrating on four primary categories: Mn–N–C electrocatalysts, manganese oxides, manganates, and other Mn-based compounds. By examining the intrinsic merits and limitations of each category, we provide a comprehensive discussion of optimization strategies, which include morphological modulation, structural engineering, carbon hybridization, heterointerface construction, heteroatom doping, and defect engineering, aimed at enhancing catalytic performance. Additionally, we critically address existing challenges and propose future research directions for Mn-based materials in rechargeable ZABs, offering theoretical insights and design principles to advance the development of next-generation energy storage systems. Full article

The complex dielectric permittivity has been studied with the waves of millimeter wavelength for rare earth manganate and titanate and LiCoPO₄ and LiNi_0.5Co_0.5PO₄ orthophosphate composites. The measurements are carried out at frequencies of 26 to 38 GHz via measurements of transmission and reflection coefficients through a plate. A special method on how to extract the real and imaginary parts of dielectric permittivity is applied. Discussion is conducted on a nonmonotonic type of the frequency dependences for both real and imaginary parts of permittivity, and it has been shown that relaxation is non-Debye. The Cole–Cole, Havriliak–Negami, and Kohlrausch–Williams–Watts models cannot also explain the nonmonotonic frequency dependence of the real part of dielectric permittivity. Investigation of the structure and phase composition of nanocomposites has been carried out. Full article

Lanthanum strontium manganate (La_1−xSr_xMnO₃) is considered a highly promising material for the development of intelligent thermal control coatings due to its exceptional properties. Recent studies on this material have primarily utilized solid-state synthesis as the main preparation method. Research efforts have predominantly focused on investigating the effects of material composition, heat treatment processes, and other factors on the properties of the synthesized material. There has been a limited amount of research investigating the influence of chemical precipitation process parameters on the properties of the synthesized La_1−xSr_xMnO₃ material. In this study, the intelligent thermal control coating material La_0.8Sr_0.2MnO₃ was synthesized using the chemical precipitation method. The effects of varying precipitant concentrations on the properties of the synthesized material were investigated. When the precipitant concentration is 12 wt.% or 15 wt.%, the synthesized powder agglomerates predominantly form three-dimensional blocky structures after sintering. At lower concentrations such as 6 wt.% and 9 wt.%, the powder agglomerates predominantly form two-dimensional sheet-like structures after sintering. At precipitant concentrations of 6 wt.% and 9 wt.%, the strontium content in the synthesized powder becomes significantly lower than the designed theoretical value. When the precipitant concentration is relatively high, localized manganese aggregation occurs in the synthesized lanthanum strontium manganate material. The temperature dependence of the emittance test result indicates that the emissivity variation of La_0.8Sr_0.2MnO₃ material synthesized using 12 wt.% ammonia solution as precipitant reaches 0.428 from 173 K to 373 K, demonstrating excellent emissivity modulation performance. Full article

Manganese (Mn) is an essential trace element and a cofactor for several key enzymes, such as mitochondrial superoxide dismutase. Consequently, it plays an important defense role against reactive oxygen species. Despite this, Mn chronic overexposure can result in a neurological disorder referred to as manganism, which shares some similarities with Parkinson’s disease. Mn levels seem regulated by many transporters responsible for its uptake and efflux. These transporters play an established role in many inherited disorders of Mn metabolism and neurotoxicity. Some inherited Mn metabolism disorders, caused by mutations of SLC30A10 and SLC39A14, assume crucial importance since earlier treatment results in a better prognosis. Physicians should be familiar with the clinical presentation of these disorders as the underlying cause of dystonia/parkinsonism and look for other accompanying features, such as liver disease and polycythemia, which are typically associated with SLC30A10 mutations. This review aims to highlight the currently known Mn transporters, Mn-related neurotoxicity, and its consequences, and it provides an overview of inherited and acquired disorders of Mn metabolism. Currently available treatments are also discussed, focusing on the most frequently encountered presentations. Full article

Fruit vinegar is typically produced through a two-stage deep liquid fermentation involving alcohol fermentation (Saccharomyces cerevisiae) and acetic acid fermentation (Acetobacter pasteurianus). In order to enhance the flavor and texture of sea buckthorn fruit vinegar, Lactobacillus fermentum was introduced into the alcoholic fermentation stage. At the end of fermentation, the total acid and acetic acid of sea buckthorn (Hippophae rhamnoides L.) fruit vinegar were both enhanced compared with sea buckthorn vinegar brewed through the traditional liquid fermentation method, and in terms of the main active ingredients, the total flavonoid content was slightly enhanced. Non-targeted metabolomics (LC-MS) was used to characterize the characteristic metabolite profiles during the fermentation process. A total of 55 differential metabolites, including organic acids, flavonoids, and amino acids, were identified, and the contents of citric acid, malic acid, and manganic acid, which are the sources of the irritating taste of sea buckthorn berry vinegar, were significantly reduced. In addition, the co-fermentation of Lactobacillus fermentum promoted both glycolysis and the TCA cycle and also led to a significant up-regulation of aromatic metabolites, such as ethyl acetate, ethyl lactate, and ethyl caproate. These results will provide new information on the dynamics of the characterized metabolites during the fermentation of sea buckthorn fruit vinegar. Full article

It is shown that molar and ionic volumes are linearly related for compounds AB₂O₄ in the spinel-, calcium-ferrate, -titanate, and -manganate structure types at ambient and at high pressure. These relations quantify the concept of ‘chemical pressure’ by relating it to thermodynamic pressure. Full article

Background: Manganese is an essential micronutrient that plays a pivotal role in environmental systems, plant physiology, and human health. This review comprehensively examines the manganese cycle in the environment, its absorption and transport mechanisms in plants, and the implications of manganese exposure to human health. Objectives: The objectives of this review are to (i) analyze the environmental cycling of manganese and its bioavailability, (ii) evaluate the role of manganese in plant metabolism and disease resistance, and (iii) assess the impact of manganese toxicity and deficiency on human health. Conclusion: This review highlights that while manganese is crucial for photosynthesis, enzyme activation, and resistance to plant diseases, both its deficiency and toxicity can have severe consequences. In plants, manganese deficiency can lead to impaired growth and reduced crop yields, while toxicity, particularly in acidic soils, can inhibit photosynthesis and stunt development. In humans, manganese is necessary for various physiological processes, but overexposure, especially in occupational settings, can result in neurodegenerative conditions such as manganism. The conclusion emphasizes the importance of managing manganese levels in agriculture and industry to optimize its benefits while minimizing health risks. A multidisciplinary approach is advocated to enhance agricultural productivity and ensure public health safety. Full article

We report on the synthesis and characterization of Mn(III) chloride (Mn^IIICl₃) complexes coordinated with N-oxide ylide ligands, namely trimethyl-N-oxide (Me₃NO) and pyridine-N-oxide (PyNO). The compounds are reactive and, while isolable in the solid-state at room temperature, readily decompose into Mn(II). For example, “[Mn^IIICl₃(ONMe₃)_n]” decomposes into the 2D polymeric network compound complex salt [Mn^II(µ-Cl)₃Mn^II(µ-ONMe₃)]_n[Mn^II(µ-Cl)₃]_n·(Me₃NO·HCl)_3n (4). The reaction of Mn^IIICl₃ with PyNO forms varied Mn(III) compounds with PyNO coordination and these react with hexamethylbenzene (HMB) to form the chlorinated organic product 1-cloromethyl-2,3,4,5,6-pentamethylbenzene (8). In contrast to N-oxide coordination to Mn(III), the reaction between [Mn^IIICl₃(OPPh₃)₂] and 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) resulted in electron transfer-forming d⁵ manganate of the [TEMPO] cation instead of TEMPO–Mn(III) adducts. The reactivity affected by N-oxide coordination is discussed through comparisons with other L–Mn^IIICl₃ complexes within the context of reduction potential. Full article

Manganese (Mn²⁺) is an abundant chemical element in the earth’s crust and is present in soil, water, and industrial environments, including mining, welding, and battery manufacturing. Manganese (Mn) is an essential metal needed as a cofactor for many enzymes to maintain proper biological functions. Excessive exposure to Mn in high doses can result in a condition known as manganism, which results in disorders of the neurological, cardiac, and pulmonary systems. The aim of this study was to assess cardiac susceptibility to manganese intoxication in Colossoma macropomum subjected to a fixed concentration of 4 mg/mL for a period of up to 96 h. This study used 45 Tambaquis (30.38 ± 3.5 g) divided into five groups of 9 animals/treatment. The treated groups were exposed to the manganese concentration for a period of 24, 48, 72, and 96 h, after which the animals’ ECGs were recorded, showing heart rate, R-R interval, P-Q interval, QRS complex duration and S-T interval. The results showed that cardiac activity decreased as the contact time increased, with an increase in the P-Q and S-T intervals. This indicates that the breakdown of circulatory homeostasis in these animals was caused by contact time with manganese. Full article

Diclofenac (DCF) is often detected in diverse aquatic bodies, and ineffective management can lead to detrimental effects on human health and ecosystems. In this study, degradation of DCF by Fe(III) and Mn(II) activating bisulfite (BS) was investigated. In the Fe(III)/Mn(II)/BS system, 93.4% DCF was degraded at 200 μM BS within 120 s, and additional research on 1000 μM BS achieved 88.4% degradation efficacy. Moreover, kinetics fitting of DCF degradation with the different BS concentrations was studied to find the two highest reaction rates (200 and 1000 μM, k_obs = 0.0297 and 0.0317 s⁻¹, respectively). Whereafter, SO₄^•− and Mn(III) were identified as the main active species at these two concentrations, respectively. Density functional theory (DFT) calculations, molecular frontier orbital theory, and surface electrostatic potential (ESP) forecast electrophilic attack sites. DCF degradation pathways by radical and non-radical ways were proposed by attack site prediction and thirteen intermediates identified by UPLC-QTOF-MS. ECOSAR software 2.2 was used for toxicity assessment. This work studied DCF degradation by the Fe(III)/Mn(II)/BS process in the presence of different concentrations of BS, providing a new insight into water purification. Full article

In recent years, a series of articles has been published concerning magnetic resonance imaging (MRI) studies in a group of patients exposed to manganism, specifically factory workers, welders, and individuals with liver diseases, as well as those abusing home-produced ephedrone. Some potential symptoms of manganese toxicity include motor disturbances, neurocognitive problems, sleep disorders, and psychosocial changes. Despite various publications on MRI research in individuals with an elevated risk of manganism, there is a noticeable absence of a comprehensive review in this field. The detection of the accumulation of manganese in the brain through MRI can confirm the diagnosis and guide appropriate treatment. Due to the high cost of determining manganese ion levels in biological material, an additional aim of the manuscript was to identify simple medical laboratory parameters that, when performed concurrently with MRI, could assist in the diagnosis of manganism. Among these types of parameters are the levels of bilirubin, magnesium, liver enzymes, creatinine, hemoglobin, and hematocrit. Full article

The expected shortage of Li due to the strong increase in electromobility is an important issue for the recovery of Li from spent Li-ion batteries. One approach is pyrometallurgical processing, during which ignoble elements such as Li, Al and Mn enter the slag system. The engineered artificial mineral (EnAM) strategy aims to efficiently recover critical elements. This study focuses on stabilizing Li-manganates in a synthetic slag and investigates the relationship between Mn⁴⁺ and Mg and Al in relation to phase formation. Therefore, three synthetic slags (Li, Mg, Al, Si, Ca, Mn, O) were synthesized. In addition to LiMn³⁺O₂, Li₂Mn⁴⁺O₃ was also stabilized. Both phases crystallized in a Ca-silicate-rich matrix. In the structures of Li₂MnO₃ and LiMnO₂, Li and Mn can substitute each other in certain proportions. As long as a mix of Mn²⁺ and Mn³⁺ is present in the slag, spinels form through the addition of Mg and/or Al. Full article

Argillaceous limestone (AL) is comprised of carbonate minerals and clay minerals and is widely distributed throughout the Earth’s crust. However, owing to its low surface area and poorly active sites, AL has been largely neglected. Herein, manganic manganous oxide (Mn₃O₄) was used to modify AL by an in-situ deposition strategy through manganese chloride and alkali stepwise treatment to improve the surface area of AL and enable its utilization as an efficient adsorbent for heavy metals removal. The surface area and cation exchange capacity (CEC) were enhanced from 3.49 to 24.5 m²/g and 5.87 to 31.5 cmoL(+)/kg with modification, respectively. The maximum adsorption capacities of lead (Pb²⁺), copper (Cu²⁺), and nickel (Ni²⁺) ions on Mn₃O₄-modified argillaceous limestone (Mn₃O₄–AL) in mono-metal systems were 148.73, 41.30, and 60.87 mg/g, respectively. In addition, the adsorption selectivity in multi-metal systems was Pb²⁺ > Cu²⁺ > Ni²⁺ in order. The adsorption process conforms to the pseudo-second-order model. In the multi-metal system, the adsorption reaches equilibrium at about 360 min. The adsorption mechanisms may involve ion exchange, precipitation, electrostatic interaction, and complexation by hydroxyl groups. These results demonstrate that Mn₃O₄ modification realized argillaceous limestone resourcization as an ideal adsorbent. Mn₃O₄-modified argillaceous limestone was promising for heavy metal-polluted water and soil treatment. Full article

The Clarion–Clipperton Fracture Zone of the east Pacific contains numerous shallow buried nodules that are in direct contact with pore water in sediment, providing a direct reflection of the interaction between nodules and sediment. However, research on the geochemical behavior of these shallow-buried nodules is limited. This study used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) to compare mineral and element distribution in shallow buried nodules with surface nodules. The shallow buried nodules are products of nodules entering the burial stage. In comparison to surface nodules, shallowly buried nodules develop a fourth oxidized-suboxic diagenetic growth layer after entering the burial stage, in addition to the three main growth inner layers (L1, L2, L3). We suggest that L4 is not influenced by the bottom water source and that the presence of todorokite and the high flux of Mn²⁺ in the sediment pore water compete with other metal elements to enter the lattice of manganate, resulting in significantly higher Mn, W, and Li contents in L4 compared to L2. However, the content of Ni, Mg, and other hydrogenetic elements is much lower in L4 compared to L2. We suggest that the instantaneous change in surface primary productivity results in a sudden shift in the redox environment of the upper sediment layer. This reaction leads to the reduction of solid-phase Mn, providing growth opportunities for the buried nodules. Simultaneously, this may also be the reason why the growth layer of the nodules is jointly controlled by the sedimentary processes of hydrogenetic, oxic diagenetic, and suboxic diagenetic processes. Full article